KR102406261B1 - Graphite-polymer composite material - Google Patents

Abstract

A graphite-polymer composite is provided. The graphite-polymer composite material according to an embodiment of the present invention has a molecular matrix, a metal support layer that forms at least one interface with the polymer matrix and includes a plurality of anchor holes penetrating upper and lower parts, and a heat dissipation filler dispersed in the polymer matrix is implemented including According to this, the composite material exhibits excellent heat dissipation performance and at the same time guarantees mechanical strength, so that it can be applied as a support for a heat source and an external housing. In addition, as it is excellent in durability, it is possible to express heat dissipation performance for a long time. Furthermore, it can be widely applied to various technical fields requiring heat dissipation due to its excellent lightness and economy.

Description

Graphite-polymer composite material

The present invention relates to a graphite-polymer composite.

Heat build-up in electronics, lights, converter housings, and other unwanted heat generating devices can shorten their operating life and reduce operating efficiency. In order to prevent this, heat dissipating members or heat dissipating devices such as heat sinks and heat exchangers are used together in devices that generate heat. come. However, the metal has a problem of heavy weight and high production cost.

Accordingly, recently, a heat dissipation member manufactured using injection molding or extrudable polymer resin has been proposed, and many studies are being conducted due to advantages such as light weight and low unit price due to the material properties of the polymer resin itself.

Among them, in consideration of the excellent moldability and heat dissipation properties of the heat dissipating member as described above, there are attempts to perform the external housing function of the heat source by itself or to have the function of a support body by itself, but due to the weak mechanical strength of the polymer resin itself, There is a problem in that it is difficult to perform the function of an external housing or support that protects the heat source by itself.

In order to solve this problem, recent attempts have been made to mold the heat dissipating member by including a support member capable of performing a support function in the heat dissipating member. As the separation occurs at the member interface, there is a problem in that the polymer resin is broken or peeled off during use.

In addition, the spaced gap may cause a decrease in heat dissipation performance, and if the polymer compound is broken or peeled off, the problem of deterioration in heat dissipation performance may become more severe.

Furthermore, when moisture penetrates between the spaced gaps, interfacial peeling is accelerated, and there may be a problem in that heat dissipation performance and mechanical strength are lowered by causing oxidation of the support member and the like.

Accordingly, it is urgent to develop a heat dissipation member with excellent durability and heat dissipation performance and mechanical strength by improving the interfacial properties between different materials.

Laid-Open Patent Publication No. 10-2016-0031103

The present invention has been devised in view of the above points, and the present invention has excellent heat dissipation performance and mechanical strength is guaranteed.

Another object of the present invention is to provide a graphite-polymer composite material that can exhibit long-term heat dissipation performance due to excellent durability.

Furthermore, another object of the present invention is to provide a housing or support member for various articles through a graphite-polymer composite having excellent heat dissipation, mechanical strength and durability.

In order to solve the above problems, the present invention includes a polymer matrix, a metal support layer that forms at least one interface with the polymer matrix and includes a plurality of anchor holes penetrating upper and lower parts, and a heat dissipation filler dispersed in the polymer matrix A graphite-polymer composite is provided.

According to an embodiment of the present invention, the cross-section of the anchor hole may be one or more types of formal or atypical shapes selected from the group consisting of a circle, an oval, a triangle, a square, a cross, and a star.

In addition, the diameter of the anchor hole may be 1 mm or more.

In addition, at least a portion of the anchor hole may be filled with the polymer matrix.

In addition, the metal support layer may further include a protrusion formed to be located in the polymer matrix by extending from at least a part of a part or all of the edge of the anchor hole in order to function as an anchor at the interface.

In addition, the protrusion may be a cut piece in which at least a portion of the metal support layer is cut.

In addition, a portion of the protrusion may protrude upward of the metal support layer, and the remainder may be formed to protrude downward of the metal support layer.

In addition, the heat dissipation filler may include a graphite composite having nanoparticles bonded to the graphite surface and functioning as an anchor at the interface formed with the metal support layer and a catecholamine layer covering the nanoparticles.

In addition, the graphite composite may further include a polymer layer covering at least the catecholamine layer.

In addition, the graphite composite may have an average particle diameter of 50 ~ 600㎛.

In addition, the heat dissipation filler may further include any one or more of graphite flakes, expanded graphite, and spherical graphite for preventing aggregation of the graphite composite. In this case, the graphite flakes, expanded graphite, or spherical graphite may have an average particle diameter of 50 to 300 μm.

In addition, any one or more of the graphite flakes, expanded graphite, and spherical graphite may be provided in an amount of 5 to 200 parts by weight based on 100 parts by weight of the graphite composite.

In addition, the polymer matrix is polyamide, polyester, polyketone, liquid crystal polymer, polyolefin, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyphenylene oxide (PPO), polyether sulfone (PES) , one compound selected from the group consisting of polyetherimide (PEI) and polyimide, or a mixture or copolymer of two or more.

In addition, the metal support layer may be one metal selected from the group consisting of aluminum, magnesium, iron, titanium, and copper, or an alloy containing at least one metal.

In addition, a protective coating layer may be further provided on the outer surface of the polymer matrix.

In addition, the protective coating layer may be a heat dissipation coating layer.

In addition, the present invention provides a heat dissipation housing comprising a graphite-polymer composite according to the present invention.

In addition, the present invention provides a heat dissipation support member comprising a graphite-polymer composite material.

According to the present invention, the graphite-polymer composite exhibits excellent heat dissipation performance and at the same time guarantees mechanical strength, so that it can be applied as a support for a heat source and an external housing. In addition, due to its excellent durability, it can express heat dissipation performance for a long time without deterioration of heat dissipation/mechanical strength even under physical/chemical stimuli such as external moisture and heat. can

1 is a graphite-polymer composite material cross-sectional view according to an embodiment of the present invention;
2 is a plan view of a metal support layer included in an embodiment of the present invention;
3A to 3E are views showing various shapes of anchor holes formed in a metal support layer included in an embodiment of the present invention;
4 to 6 is a graphite-polymer composite material cross-sectional view according to various embodiments of the present invention;
7 is a view of a graphite composite as an example of a heat dissipation filler included in an embodiment of the present invention, Figure 7a is a perspective view of the graphite composite, Figure 7b is a view showing a cross-sectional view along the X-X' boundary of Figure 7a,
8 is a view showing a cross-sectional view of a graphite composite, which is an example of a heat dissipation filler included in an embodiment of the present invention, and
9 is a cross-sectional view of a graphite composite, which is a heat dissipation filler included in an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily carry out the present invention. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and the same reference numerals are added to the same or similar elements throughout the specification.

Referring to FIG. 1 , a graphite-polymer composite 1000 according to an embodiment of the present invention includes a polymer matrix 200 , a metal support layer forming at least one interface with the polymer matrix 200 , 300 and the polymer It is implemented as a heat dissipation filler 100 dispersed on a matrix.

First, the polymer matrix 200 will be described.

The polymer matrix 200 has good compatibility with the metal support layer 300 and the heat dissipation filler 100 to be described later, and is preferably made of a polymer compound that can be injection molded without affecting the dispersion of the heat dissipation filler 100 . If it is, there is no limitation. As a preferred example, the polymer matrix 200 may be a known thermoplastic polymer compound. The thermoplastic polymer compound is preferably polyamide, polyester, polyketone, liquid crystal polymer, polyolefin, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyphenylene oxide (PPO), polyether sulfone ( PES), polyetherimide (PEI), and one kind of compound selected from the group consisting of polyimide, or a mixture or copolymer of two or more kinds.

For example, the polyamide may be a known polyamide-based compound such as nylon 6, nylon 66, nylon 11, nylon 610, nylon 12, nylon 46, nylon 9T (PA-9T), Kiana and aramid.

For example, the polyester may be a known polyester-based compound such as polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), or polycarbonate.

For example, the polyolefin may be a known polyolefin-based compound such as polyethylene, polypropylene, polystyrene, polyisobutylene, or ethylene vinyl alcohol.

The liquid crystal polymer may be used without limitation in the case of a polymer exhibiting liquid crystallinity in a solution or dissolved state, and may be a known type, so that the present invention is not particularly limited thereto.

Next, the metal support layer 300 will be described.

The metal support layer 300 is a graphite-polymer composite material 1000 that guarantees mechanical strength and exhibits a predetermined heat dissipation performance. The metal support layer 300 has excellent compatibility with the above-described polymer matrix, so that it is not easily separated from the interface between the polymer matrix 200 and the metal support layer 300 and has excellent mechanical strength even with a thin thickness, and can be injection molded In the case of a metal material having a certain degree of heat resistance and a predetermined thermal conductivity at the same time, it can be used without limitation. As a non-limiting example, the metal support layer 300 may be one type of metal selected from the group consisting of aluminum, magnesium, iron, titanium, and copper, or an alloy containing at least one type of metal.

However, due to the material difference from the above-described polymer matrix 200, the bonding characteristics of the interface between the polymer matrix 200 and the metal support layer 300 may not be good. There is a risk of corrosion of the metal support layer 300 due to the occurrence of cracks or peeling of the matrix 200 or the accelerated inflow of moisture and air into the separated gap.

Accordingly, in order to increase the bonding force between the polymer matrix 200 and the metal support layer 300 by improving the interfacial properties formed in contact with them, the metal support layer 300 has a plurality of anchor holes (H) penetrating the upper and lower surfaces. In the graphite-polymer composite, the anchor hole (H) may be filled with the polymer matrix 200 to structurally increase the bonding force between the polymer matrix 200 and the metal support layer 300 .

The anchor hole H formed in the metal support layer 300 may have a diameter sufficient to allow the polymer matrix 200 to penetrate and be easily filled in the anchor hole H. For example, the anchor hole H The diameter (d in Fig. 2) may be 1 mm or more, preferably 1 to 50 mm, more preferably 1 to 30 mm, still more preferably 1 to 10 mm. If the diameter of the anchor hole (H) is less than 1 mm, it may be difficult to completely fill the polymer matrix by penetrating into the anchor hole. If the anchor hole is not completely filled, the improvement in the bonding strength of the interface may be insignificant, and there is a fear that the heat dissipation performance may be rather deteriorated according to the expression of the thermal insulation effect due to the air filled in the empty space inside the anchor hole. In addition, if the diameter of the anchor hole (H) exceeds 50 mm, the interfacial bonding property between the polymer matrix and the metal support layer may be further improved, but the heat dissipation property due to the metal support layer may be deteriorated, and there is a risk of a decrease in mechanical strength .

The anchor holes (H) are distributed at uniform intervals along the width and length directions of the metal support layer 300 or are formed by varying the spacing between the anchor holes (H) for each location. A distribution ratio in which the holes H are provided may be different. The spacing between the anchor holes (H) (p in FIG. 2 ) may be, for example, 5 to 20 mm. As the spacing between anchor holes (H) is narrower, the bonding characteristics may be improved, but there is a risk of deterioration in heat dissipation performance and mechanical strength of the metal support layer, and the greater the spacing of the anchor holes (H), the greater the risk of deterioration in bonding characteristics.

The anchor hole (H) may have one or more regular shapes (refer to FIGS. 2, 3A to 3E) or an atypical shape selected from the group consisting of a circle, an oval, a triangle, a square, a cross, and a star in cross section. In addition, the cross-sectional shapes of the plurality of anchor holes H provided in the metal support layer 300 may be all the same, or some or all of them may be different.

Since the anchor hole (H) can be formed through a perforation by a known method, a detailed description of the method for forming the anchor hole (H) is omitted in the present invention.

On the other hand, as shown in FIGS. 4 to 6, the graphite-polymer composite material 1001, 1002, 1003 is a metal support layer 301, 302, 303 in order to express more improved bonding properties with the polymer matrix 200, and an anchor hole (H'). ) may further include protrusions 311 , 312 , 313 , 314 formed to extend from at least a portion of the edge. The protrusions 311, 312, 313, 314 function as anchors in the polymer matrix 200, and the bonding properties between the polymer matrix 200 and the metal support layers 301, 302, 303 can be structurally further improved together with the anchor holes (H, H') described above. have.

The protrusions 311 , 312 , 313 , and 314 may have a shape in which the punched, stamped or pressed portion is cut by punching, stamping, or pressing on the upper side of the metal support layer 301 , 302 , 303 . However, the method of forming the protrusions 311 , 312 , 313 , and 314 is not limited thereto, and at least a portion from the metal support layer 301 , 302 , 303 may be formed through various methods as long as it extends from the edge of the anchor groove H and protrudes.

The protrusions 311 , 312 , 313 , and 314 may extend from the entire edge to protrude upward as shown in FIG. 4 , or may extend from one edge to protrude upward as shown in FIGS. 5 and 6 .

In addition, the protrusions 311 , 312 , 313 , and 314 may have a shape in which the middle is bent as shown in FIGS. 5 and 6 , and through this, the bonding characteristics between the polymer matrix 200 and the metal support layers 301 , 302 , 303 can be structurally further increased. The bent shape of the protrusions 311 , 312 , 313 , and 314 is not limited to FIGS. 5 and 6 , and by having a structurally complex shape without being difficult to manufacture, structural bonding characteristics may be further improved.

On the other hand, as shown in FIG. 6 , some of the protrusions 313 and 314 provided in the metal support layer 303 protrude upward and the rest protrude downward, through which the upper and lower portions of the metal support layer 303 . It is possible to improve the interfacial bonding characteristics between each part of the polymer matrix 200 and the metal support layer 303 positioned in the .

In addition, as shown in FIGS. 1, 4 and 6, the metal support layers 300, 301, and 303 are provided so that the entire surface is surrounded by the polymer matrix 200, or as shown in FIG. 5, the lower surface of the metal support layer 302 is It may be provided in the polymer matrix 200 to be exposed, and although not shown, the upper surface of the metal support layer may be in contact with the polymer matrix, and the side and lower surfaces may be exposed, etc. The specific location of the metal support layer in the polymer matrix 200 is not particularly limited in the present invention.

In addition, the thickness of the metal support layers 300 , 301 , 302 , and 303 may be 0.5 to 90% or more with respect to the total thickness of the graphite-polymer composite material 1000 , 1001 , 1002 , 1003 . If the thickness of the metal support layer (300, 301, 302, 303) is less than 0.5% of the total thickness of the graphite-polymer composite (1000, 1001, 1002, 1003), it may be difficult to guarantee the desired level of mechanical strength, and if it exceeds 90% In this case, it is difficult to express the desired level of heat dissipation performance, especially the radiation characteristics, and the formability into complex shapes may also be deteriorated. However, the present invention is not limited thereto, and the thickness of the metal support layers 300 , 301 , 302 , and 303 may be appropriately changed in consideration of the mechanical strength required for the graphite-polymer composite material.

In addition, the metal support layer (300, 301, 302, 303) is a rod shape having a predetermined aspect ratio, a plate shape having a predetermined area, or a plurality of wires or bars inside a border wire or bar having a predetermined shape such as a square or a circle are spaced apart at a predetermined interval. , a parallel structure, a lattice structure, a honeycomb structure, and a shape having various structures combined with each other.

Next, the heat dissipation filler 100 dispersed in the polymer matrix 200 will be described.

The heat dissipation filler 100 may be used without limitation if it is a filler formed of a material known to have thermal conductivity, and may be a metal, alloy, ceramic, or carbon-based filler. Preferably, the heat dissipation filler 100 is a catecholamine layer 30 covering the nanoparticles 20 and the nanoparticles 20 bonded to the graphite surface 10, as shown in FIGS. 7a and 7b. It may include a graphite composite 101 provided.

The graphite 10 is a mineral in which planar macromolecules in which 6-membered rings of carbon atoms are infinitely connected in a plane are layered on top of each other, and may be of a type known in the art, specifically impression graphite, highly crystalline graphite and earth graphite. It may be any one of natural graphite or artificial graphite. When the graphite 10 is natural graphite, for example, it may be expanded graphite obtained by expanding impression graphite. The artificial graphite may be prepared through a known method. For example, a thermosetting resin such as polyimide is produced in a film shape of 25 μm or less and graphitized at a high temperature of 2500° C. or higher to produce single-crystal graphite, or a hydrocarbon such as methane is thermally decomposed at a high temperature to form a chemical vapor deposition method (CVD). ) to produce highly oriented graphite.

In addition, the shape of the graphite 10 may be a known shape, such as a spherical shape, a plate shape, or a needle shape, or an atypical shape, and may be a plate shape, for example.

In addition, the average particle diameter of the graphite 10 may be 50 ~ 600㎛, for example, may be 300㎛.

In addition, the graphite 10 may be high-purity graphite having a purity of 99% or more, which may be advantageous in expressing more improved physical properties.

Next, the nanoparticles 20 bonded to the surface of the above-described graphite 10 are a medium capable of providing a catecholamine layer 30 to be described later on the graphite 10, and at the same time, the graphite composite 101 is a metal support layer 300 ) and functions as an anchor when forming an interface, thereby preventing the separation phenomenon in which the polymer matrix 200 floats in the metal support layer 300 due to the graphite composite 101 .

First, if the mediator for the formation of the catecholamine layer 30 is described, the surface of the above-described graphite 10 is hardly provided with a functional group that can mediate a chemical reaction, so that of the graphite 10 in the polymer matrix, which is a heterogeneous material. It is difficult to disperse, and the injected graphite tends to agglomerate and exist. As a method of preventing this and improving the dispersibility in the polymer matrix, a method of providing a catecholamine layer on graphite can be considered, but even catecholamine-based compounds known to be excellent in compatibility and compatibility with different materials are provided on graphite Since it is not easy to do, there is a problem that the amount of the catecholamine-based compound remaining in the actual graphite is very small even if the catecholamine-based compound is treated on the graphite. In addition, in order to solve this problem, there is a limitation in providing the modified graphite surface with an increased amount of the catecholamine-based compound even when a modification treatment is performed to provide a functional group on the surface of the graphite.

However, in the case of the graphite 10 provided on the surface of the nanoparticles 20, there is an advantage that the catecholamine-based compound can be introduced into the graphite in a desired amount as the catecholamine-based compound is easily bound on the surface of the nanoparticles.

Next, the function as an anchor of the nanoparticles 20 will be described. The metal support layer 300, 301, 302, 303 provided to improve the mechanical strength of the graphite-polymer composite material (1000, 1001, 1002, 1003) is a conventional heat dissipation filler and/or due to the lack of compatibility with a heterogeneous polymer compound, if the heat dissipation filler When the metal support layer is disposed adjacent to the metal support layer to form an interface between the two materials, since the interface has little bonding force, it is easy to cause the polymer matrix 200 to float away from the metal support layer 300 at the interface portion. Specifically, in the case of a heat dissipation filler in which nanoparticles are not formed on the surface, an interface may be formed by contacting the metal support layer 300. Due to the dissimilar material, interfacial bonding strength may be lowered, and separation may occur at the interface. The separation may cause a larger separation due to vibration or the like, and eventually cracks and peeling of the polymer matrix 200 may be induced in the corresponding portion. In addition, the metal support layer 300 has poor interfacial bonding strength even with the polymer matrix 200, which is a heterogeneous material, so if the period of use of the graphite-polymer composite material is prolonged, lifting of the interface between them or peeling of the polymer matrix may occur. There is a concern that

However, in the case of the graphite composite 101 in which the nanoparticles 20 are formed on the graphite 10, the nanoparticles 20 function as an anchor at the interface between the graphite 10 and the metal support layer 300, so excellent bonding at the interface Characteristics can be expressed, and if the material of the nanoparticles 20 is metal, the interface bonding property can be more advantageous. Separation phenomenon can be significantly reduced.

The nanoparticles 20 may be a metal or non-metal material that exists as a solid at room temperature, and non-limiting examples thereof include alkali metals, alkaline earth metals, lanthanides, actinides, transition metals, post-transition metals, It may be selected from metalloids and the like. For example, the nanoparticles may be Ni, Si, Ti, Cr, Mn, Fe, Co, Cu, Sn, In, Pt, Au, Mg, and combinations thereof, preferably Cu, Ni or Si.

In addition, the nanoparticles 20 may have an average particle diameter of 10 to 500 nm, preferably 10 to 300 nm.

In addition, the nanoparticles 20 are preferably in a crystallized particle state, and may be provided so as to occupy an area of 10 to 70%, more preferably 30 to 70% of the total surface area of individual graphite 10 . have. In addition, the nanoparticles 20 may be provided in an amount of 5 to 70% by weight, preferably 20 to 50% by weight, based on the total weight of the graphite composite 101 . At this time, the nanoparticles 20 may express a stronger bonding force by forming a chemical bond with the graphite 10 .

Next, the catecholamine layer 30 provided on the surface of the above-described nanoparticles 20 will be described. The catecholamine layer 30 improves the excellent fluidity, dispersibility, and interfacial bonding properties between the graphite composite and the high molecular compound in the high molecular compound of different materials, and at the same time, the graphite composite 101 interfaces with the above-described metal support layer 300 When forming a polymer matrix 200 occurring on the surface of the metal support layer 300 by performing a function of improving the bonding strength between the graphite composite 101 and the metal support layer 300, 301, 302, 303 at the interface can be significantly reduced. . In addition, the catecholamine layer 30 has a reducing power by itself and at the same time forms a covalent bond with the amine functional group to the catechol functional group on the surface of the layer by Michael addition reaction, so that the catecholamine layer is used as an adhesive material for secondary surface modification This is possible, and for example, it may function as a bonding material capable of introducing the polymer layer 40 to the graphite 10 to express more improved dispersibility in the polymer compound.

The catecholamine-based compound forming the catecholamine layer 30 refers to a single molecule having a hydroxyl group (-OH) as an ortho-group of a benzene ring, and various alkylamines as a para-group As a non-limiting example of various derivatives of these constructs, dopamine, dopamine-quinone, epinephrine, alpha-methyldopamine, norepinephrine, alpha -Methyl dopa (alphamethyldopa), droxidopa (droxidopa), indolamine (indolamine), serotonin (serotonin) or 5-hydroxydopamine (5-Hydroxydopamine), etc. may be, for example, the catecholamine layer 30 is dopamine (dopamine) layer. The dopamine is a monomolecular substance having a molecular weight of 153 (Da) having catechol and an amine functional group. For example, a substance to be surface-modified in an aqueous solution under basic pH conditions (about pH 8.5) containing dopamine represented by the following Chemical Formula 1 is added. If it is put in and taken out after a certain period of time, a polydopamine (pDA) coating layer may be formed on the surface of the material by oxidation of catechol.

[Formula 1]

In Formula 1, at least one of R ₁ , R ₂ , R ₃ , R ₄ and R ₅ is a thiol, a primary amine, a secondary amine, a nitrile, an aldehyde, respectively ), imidazole, azide, halide, polyhexamethylene dithiocarbonate, hydroxyl, carboxylic acid, carboxylic ester ester) or one selected from the group consisting of carboxamide, and the rest may be hydrogen.

In addition, the thickness of the catecholamine layer 30 may be 5 to 100 nm, but is not limited thereto.

On the other hand, as shown in FIG. 9, a polymer layer 40' may be further coated on the catecholamine layer 30' of the graphite composite 101', and a polymer compound forming a matrix of the composite material due to the polymer layer 40' The compatibility with and compatibility is increased, and thus more improved fluidity, dispersibility and interfacial bonding properties of the heat dissipation filler can be realized. The polymer layer 40' may be implemented with a thermosetting polymer compound or a thermoplastic polymer compound, and specific types of the thermosetting polymer compound and the thermoplastic polymer compound may be known. As a non-limiting example, the thermosetting polymer compound may be one compound selected from the group consisting of epoxy-based, urethane-based, ester-based and polyimide-based resins, or a mixture or copolymer of two or more types. The thermoplastic polymer compound is polyamide, polyester, polyketone, liquid crystal polymer, polyolefin, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyphenylene oxide (PPO), polyether sulfone (PES), It may be one kind of compound selected from the group consisting of polyetherimide (PEI) and polyimide, or a mixture or copolymer of two or more kinds. Alternatively, the polymer layer may be a rubber elastomer including natural rubber and/or synthetic rubber and a similar material thereof.

When the polymer layer 40' is further provided, the polymer layer may have a thickness of 0.1 to 1000 nm. In addition, the polymer layer 40' may be included in an amount of 0.01 to 20% by weight based on the total weight of the graphite composite.

The above-mentioned graphite composite 101 can be prepared by performing the steps of forming nanoparticles on the graphite surface and forming a catecholamine layer on the nanoparticles, and the step of forming a polymer layer on the catecholamine layer is further can be done

First, the step of forming nanoparticles on the graphite surface may be employed without limitation if it is a known method for forming nanoparticles on the graphite surface, and is not limited thereto. As the synthesis technology, methods such as Inert Gas Condensation (IGC), Chemical Vapor Condensation (CVC), and Metal Salt Spray-Drying may be employed. However, among them, the inert gas condensation (IGC) process is capable of producing ultra-fine nanoparticle powder with high purity, but it requires a lot of energy, and the production rate is very low, so there is a limit to industrial application, and chemical vapor condensation (CVC) The process is somewhat improved in terms of energy and production rate compared to the inert gas condensation (IGC) process, but it may be uneconomical because the price of a precursor, a raw material, is very high. In addition, the metal salt spray drying process is economical because cheap salt is used as a raw material, but pollution and agglomeration of the powder cannot be avoided in the drying step, and toxic by-products are generated, which is disadvantageous in terms of environment.

Preferably, nanoparticles can be formed on the graphite through atmospheric pressure high-frequency thermal plasma. Specifically, mixing the graphite and the nanoparticle-forming powder m injecting a gas into the prepared mixture, vaporizing the nanoparticle-forming material through a high-frequency thermal plasma, and crystallizing the vaporized nanoparticle-forming material on the graphite surface This can be done through steps.

In the step of mixing the graphite and the nanoparticle-forming powder, the mixing ratio between the two materials may be designed differently depending on the purpose, but preferably, the nanoparticle-forming material is added to 100 parts by weight of graphite in order to provide nanoparticles with high density from 10 to It can be mixed in 200 parts by weight. At this time, it may be mixed using a separate stirrer.

Next, a gas may be injected into the mixed mixture, and the injected gas may be classified into a sheath gas, a central gas, a carrier gas, etc. according to its function, and these gases include an inert gas such as argon, hydrogen, nitrogen, or A gas in which they are mixed may be used, and argon gas may be preferably used. The sheath gas is injected to prevent attachment of vaporized nanoparticles to the inner surface of the wall and also to protect the wall surface from ultra-high temperature plasma, and 30 to 80 lpm (liters per minute) of argon gas can be used. In addition, the central gas is a gas injected to generate a high-temperature thermal plasma, and 30 to 70 lpm of argon gas may be used. In addition, the carrier gas is a gas serving to supply the mixture into the plasma reactor, and 5 to 15 lpm of argon gas may be used.

Next, the nanoparticle-forming material can be vaporized through high-frequency thermal plasma. The thermal plasma is an ionizing gas composed of electrons, ions, atoms and molecules generated by a plasma torch using a direct current arc or high-frequency inductively coupled discharge. . Accordingly, 10 to 70 kW of power is supplied to the power supply device of the plasma device in order to smoothly generate high-temperature plasma, an arc is formed by electric energy, and about 10,000 by argon gas used as a thermal plasma generating gas An ultra-high temperature plasma of K is generated. As described above, the ultra-high temperature thermal plasma generated by using argon gas as the generating gas while maintaining the power of 10 to 70 kW has the effect of being generated at a higher temperature than the thermal plasma generated by the heat treatment method or the combustion method. In this case, in the present invention, a known high-frequency thermal plasma (RF) method may be appropriately modified and used, and an existing thermal plasma processing apparatus may be used.

Next, a step of crystallizing the vaporized nanoparticle-forming material on the graphite surface may be performed. In order to crystallize the vaporized nanoparticle-forming material on the graphite surface, a quenching gas may be used. At this time, it can be crystallized while suppressing the growth of nanoparticles by condensing or quenching with the quenching gas.

Thereafter, to perform the step of forming a catecholamine layer on the graphite in which nanoparticles are formed, specifically dipping the graphite in which nanoparticles are formed in a weakly basic aqueous dopamine solution; and forming a polydopamine layer on the graphite surface on which the nanoparticles are formed.

First, the method for preparing the weakly basic dopamine aqueous solution is not particularly limited, but a tris buffer solution (10 mM, tris buffer solution) with a pH of 8 to 14 basic, more preferably a basic tris with a pH of 8.5, which is the same basic condition as the environment in the sea It can be prepared by dissolving dopamine in a buffer solution, and in this case, the dopamine concentration of the weakly basic dopamine aqueous solution may be 0.1 to 5 mg/ml, preferably 2 mg/ml.

After dipping the graphite in which nanoparticles are formed in the prepared weakly basic dopamine aqueous solution, dopamine undergoes a spontaneous polymerization reaction under basic and oxidizing conditions to form a catecholamine layer, which is a polydopamine layer, on the graphite in which nanoparticles are formed. In this case, a polydopamine layer may be formed by further providing an oxidizing agent, and oxygen gas in the air may be used as an oxidizing agent without an oxidizing agent, and the present invention is not particularly limited thereto.

At this time, the dipping time determines the thickness of the polydopamine layer. In the case of using an aqueous dopamine solution having a pH of 8 to 14 and a dopamine concentration of 0.1 to 5M, in order to form a catecholamine layer to a thickness of 5 to 100 nm, preferably about 0.5 to 24 Dipping for hours is preferred. In pure plate-like graphite, a dopamine coating layer is hardly formed on the graphite surface through this method, but a catecholamine layer may be formed on the nanoparticles due to the nanoparticles.

Thereafter, a polymer layer may be further formed on the catecholamine layer. The polymer layer may be formed through a method of dipping in a polymer layer-forming composition to form a graphite complex in which a catecholamine layer is formed. However, it is not limited thereto, and polymers through known methods such as blade coating, flow coating, casting, printing method, transfer method, brushing, or spraying layer can be formed. The polymer layer-forming composition may be a dissolved solution or a molten solution in which a desired polymer compound is dissolved. In this case, the thickness of the polymer layer to be formed may be appropriately changed in consideration of material properties such as compatibility between the polymer compound forming the polymer layer and the polymer compound forming the polymer matrix described above.

In addition, the graphite according to an embodiment of the present invention - the polymer composite (1000, 1001, 1002, 1003) is a heat dissipation filler 100, suppressing aggregation of the graphite composite 101, the graphite composite 101 is a polymer matrix ( 200), and may further include any one or more of graphite flakes, expanded graphite, and spherical graphite for the implementation of a lighter composite material. The above-described graphite composite may further include a catecholamine layer to improve fluidity, dispersibility, and interfacial bonding properties when mixed with a high molecular compound, but when the content of the provided catecholamine layer increases, rather the graphite due to the catecholamine layer Aggregation of the composites may occur, and this can be prevented by further providing any one or more of the graphite flakes, expanded graphite, and spherical graphite, and the implemented composite material has uniform mechanical strength, heat dissipation characteristics, and electromagnetic waves for each area. It can be made to express physical properties, such as shielding. In addition, in addition to this, the spherical graphite improves the vertical thermal conductivity of the graphite-polymer composite, and the expanded graphite may further improve the thermal conductivity of the graphite-polymer composite.

Any one or more of the graphite flakes, expanded graphite, and spherical graphite may have an average particle diameter of 50 to 300 μm.

In addition, any one or more of the graphite flakes, expanded graphite, and spherical graphite may be included in an amount of 5 to 200 parts by weight based on 100 parts by weight of the graphite composite. If the heat dissipation filler provided in addition to the graphite composite is provided in less than 5 parts by weight, the degree of improvement in heat dissipation performance due to different types of heat dissipation filler is insignificant, it may be difficult to prevent aggregation of the graphite composite, and most of the heat dissipation filler is made of graphite There is a risk of cost increase due to having to be provided as a composite, which may be undesirable for weight reduction of the implemented composite material. In addition, if the additionally provided heat dissipation filler is provided in excess of 200 parts by weight, the composite material implemented through this may not be able to express the desired level of thermal conductivity and mechanical strength, and the interfacial bonding property is lowered, so that the polymer matrix and the metal support layer The spacing may become more frequent and severe, and the heat dissipation filler fluidity may decrease during the manufacturing process of the composite material, so that it may be concentrated in the center rather than the surface portion of the composite material, so that the radiation characteristics of the conducted heat may be significantly reduced.

On the other hand, the graphite-polymer composite material 1000 may further include other additives such as strength improvers, impact modifiers, antioxidants, heat stabilizers, light stabilizers, plasticizers, dispersants, work improvers, coupling agents, UV absorbers, antistatic agents, flame retardants, etc. can

The strength improving agent can be used without limitation in the case of known components capable of improving the strength of the graphite-polymer composite material, and non-limiting examples thereof include carbon fibers, glass fibers, glass beads, zirconium oxide, wollastonite, From the group consisting of gibbsite, boehmite, magnesium aluminate, dolomite, calcium carbonate, magnesium carbonate, mica, talc, silicon carbide, kaolin, calcium sulfate, barium sulfate, silicon dioxide, ammonium hydroxide, magnesium hydroxide and aluminum hydroxide One or more selected ingredients may be included as a strength improving agent. The strength improving agent may be included in an amount of 0.5 to 200 parts by weight based on 100 parts by weight of the heat dissipation filler, but is not limited thereto. For example, when glass fiber is used as the strength improving agent, the diameter of the glass fiber may be 2 to 8 mm.

In addition, the impact modifier may be used without limitation in the case of known components capable of improving the impact resistance by expressing the flexibility and stress relaxation properties of the graphite-polymer composite, and may be, for example, a thermoplastic resin. Also, as an example, it may be a rubber-based resin. The rubber-based resin may be natural rubber or synthetic rubber. The synthetic rubber is styrene butadiene rubber (SBR), butadiene rubber (BR), chloroprene rubber (CR), isoprene rubber (IR), isobutene isoprene rubber (isobutene isoprene rubber) , IIR), nitrile-butadiene rubber (NBR), ethylene propylene rubber (EPR), ethylene propylene diene monomer rubber, acrylic rubber, silicone rubber, It may be at least one selected from the group consisting of fluorine rubber and urethane rubber, but is not limited thereto.

In addition, the impact modifier may be an elastic particle having a core/shell structure. For example, an allyl-based resin may be used for the core, and the shell portion may be a polymer resin having a functional group capable of reacting to increase compatibility and bonding strength with a thermoplastic polymer compound. In addition, the impact modifier may be included in an amount of 0.5 to 200 parts by weight based on 100 parts by weight of the heat dissipation filler, but is not limited thereto.

In addition, the antioxidant is provided to prevent breakage of the main chain of a polymer matrix forming a polymer matrix by shear during extrusion and injection, for example, a thermoplastic polymer compound, and to prevent heat discoloration. As the antioxidant, known antioxidants may be used without limitation, and non-limiting examples thereof include tris(nonylphenyl)phosphite, tris(2,4-di-t-butylphenyl)phosphite, and bis(2). organophosphites such as ,4-di-t-butylphenyl)pentaerythritol diphosphite, distearyl pentaerythritol diphosphite or the like; alkylated monophenols or polyphenols; alkylated reaction products of polyphenols with dienes, such as tetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)]methane, or the like; butylated reaction products of para-cresol or dicyclopentadiene; alkylated hydroquinones; hydroxylated thiodiphenyl ether; alkylidene-bisphenol; benzyl compounds; esters of monohydric or polyhydric alcohols with beta-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid; esters of monohydric or polyhydric alcohols with beta-(5-tert-butyl-4-hydroxy-3-methylphenyl)-propionic acid; Distearylthiopropionate, dilaurylthiopropionate, ditridecylthiopropionate, octadecyl-3-(3,5-di-tert-butyl-l-4-hydroxyphenyl)propionate , esters of thioalkyl or thioaryl compounds such as pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate or the like; amides of beta-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid or the like, or mixtures thereof. The antioxidant may be provided in an amount of 0.01 to 0.5 parts by weight based on 100 parts by weight of the polymer compound forming the polymer matrix.

In addition, the heat stabilizer can be used without limitation in the case of known heat stabilizers, but non-limiting examples thereof include triphenyl phosphite, tris-(2,6-dimethylphenyl)phosphite, tris-(mixed mono-) organic phosphites such as tris-(mixed mono-and di-nonylphenyl)phosphate or the like; phosphonates such as dimethylbenzene phosphonate or the like, phosphates such as trimethyl phosphate, or the like, or mixtures thereof. The heat stabilizer may be included in an amount of 0.01 to 0.5 parts by weight based on 100 parts by weight of the polymer compound forming the polymer matrix.

In addition, the light stabilizer may be used without limitation in the case of a known light stabilizer, but non-limiting examples thereof include, for example, 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy-5 benzotriazoles or mixtures thereof, such as -tert-octylphenyl)-benzotriazole and 2-hydroxy-4-n-octoxy benzophenone or the like. The light stabilizer may be included in an amount of 0.1 to 1.0 parts by weight based on 100 parts by weight of the polymer compound forming the polymer matrix.

In addition, the plasticizer may be used without limitation in the case of known plasticizers, but non-limiting examples thereof include dioctyl-4,5-epoxy-hexahydrophthalate, tris-(octoxycarbonylethyl)isocyanurate, phthalic acid esters such as tristearin, epoxidized soybean oil or the like, or mixtures thereof. The plasticizer may be included in an amount of 0.5 to 3.0 parts by weight based on 100 parts by weight of the polymer compound forming the polymer matrix.

In addition, as the antistatic agent, a known antistatic agent may be used without limitation, and non-limiting examples thereof include glycerol monostearate, sodium stearyl sulfonate, sodium dodecylbenzenesulfonate, polyether block. amides, or mixtures thereof, which include, for example, BASF under the trade name Irgastat; Arkema under the trade name PEBAX; and from Sanyo Chemical industries under the trade name Pelestat. The antistatic agent may be included in an amount of 0.1 to 1.0 parts by weight based on 100 parts by weight of the polymer compound forming the polymer matrix.

In addition, as the work improving agent, known work improving agents may be used without limitation, and non-limiting examples thereof include metal stearate, stearyl stearate, pentaerythritol tetrastearate, beeswax, and montan wax. wax), paraffin wax, polyethylene wax or the like, or mixtures thereof. The work improving agent may be included in an amount of 0.1 to 1.0 parts by weight based on 100 parts by weight of the polymer compound forming the polymer matrix.

In addition, as the UV absorber, a known UV absorber may be used without limitation, and non-limiting examples thereof include hydroxybenzophenone; hydroxybenzotriazole; hydroxybenzotriazine; cyanoacrylate; oxanilides; benzoxazinones; 2-(2H-Benzotriazol-2-yl)-4-(1,1,3,3,-tetramethylbutyl)-phenol; 2-hydroxy-4-n-octyloxybenzophenone; 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)-phenol; 2,2'-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one); 1,3-bis[(2-cyano-3,3-diphenylacryloyl)oxy]-2,2-bis[[(2-cyano-3,3-biphenylacryloyl)oxy] methyl]propane; 2,2′-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one); 1,3-bis[(2-cyano-3,3-diphenylacryloyl)oxy]-2,2-bis[[(2-cyano-3,3-diphenylacryloyl)oxy] methyl]propane; nano-sized inorganic materials such as titanium oxide, cerium oxide and zinc oxide having a particle diameter of less than 100 nm; or the like, or mixtures thereof. The UV absorber may be included in an amount of 0.01 to 3.0 parts by weight based on 100 parts by weight of the polymer compound forming the polymer matrix.

In addition, the coupling agent may be a known coupling agent without limitation, and as an example thereof, may be maleic acid-grafted polypropylene. The coupling agent may be included in an amount of 0.01 to 10.0 parts by weight based on 100 parts by weight of the polymer compound forming the polymer matrix.

In addition, the flame retardants include, for example, halogenated flame retardants, like tretabromo bisphenol A oligomers such as BC58 and BC52, brominated polystyrene or poly(dibromo-styrene), brominated epoxies, Decabromodiphenyleneoxide, pentabromopenzyl acrylate monomer, pentabromobenzyl acrylate polymer, ethylene-bis(tetrabromophthalimide, bis(pentabromobenzyl)ethane, Mg(OH) ₂ and Al ( metal hydroxides such as OH) ₃ , melamine cyanurate, phosphor-based FR systems such as red phosphorus, melamine polyphosphates, phosphate esters, metal phosphinates, ammonium polyphosphates, expandable graphite , sodium or potassium perfluorobutane sulfate, sodium or potassium perfluorooctane sulfate, sodium or potassium diphenylsulfonesulfonate and sodium- or potassium-2,4,6,-trichlorobenzonate and N-(p- Tolylsulfonyl)-p-toluenesulfimide potassium salt, N-(N'-benzylaminocarbonyl) sulfanylimide potassium salt, or mixtures thereof, including, but not limited to, the flame retardant is a polymer matrix. It may be included in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the polymer compound forming the .

The graphite-polymer composite material (1000, 1001, 1002, 1003) according to an embodiment of the present invention described above is a metal support layer (300, 301, 302, 303) is coated, impregnated or injected in a solution or melt of a polymer compound including a dispersed heat dissipation filler. , can be manufactured through a known molding method such as extrusion, and then subjected to a solidification process such as curing, drying and/or cooling. As the conditions according to can be designed differently, the present invention is not particularly limited thereto.

In addition, the graphite-polymer composite material (1000, 1001, 1002, 1003) may further include a protective coating layer 400 on the outer surface of the polymer matrix (200). The protective coating layer 400 prevents separation of the heat dissipation filler 100 located on the surface of the polymer matrix, prevents scratches due to physical stimulation applied to the surface, and provides an insulating function depending on the material to provide insulation and heat dissipation At the same time, it can be used for applications such as required electronic devices.

The protective coating layer 400 may be implemented with a known thermosetting polymer compound or a thermoplastic polymer compound. The thermosetting high molecular compound may be one compound selected from the group consisting of epoxy-based, urethane-based, ester-based and polyimide-based resins, or a mixture or copolymer of two or more types. In addition, the thermoplastic polymer compound is polyamide, polyester, polyketone, liquid crystal polymer, polyolefin, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyphenylene oxide (PPO), polyether sulfone (PES) ), polyetherimide (PEI), and one compound selected from the group consisting of polyimide, or a mixture or copolymer of two or more types, but is not limited thereto.

The protective coating layer 400 may have a thickness of 0.1 to 1000 μm, but is not limited thereto, and may be implemented by changing it according to the purpose.

On the other hand, the protective coating layer 400 may interfere with the radiation of heat conducted through the heat dissipation filler 100 and the metal support layer 300 in the air. Accordingly, in order to express more improved heat dissipation, in particular, heat radiation characteristics to the outside air, the protective coating layer 400 may be a heat dissipation coating layer further having a heat dissipation filler. The heat dissipation filler can be used without limitation in the case of a known heat dissipation filler, if insulation is required at the same time, at least one insulating heat dissipation filler selected from the group consisting of aluminum oxide, boron nitride, talc, magnesium oxide, silicon carbide, etc. It is preferable to have

The type, particle size, content, etc. of the heat dissipation filler provided in the protective coating layer 400 may be designed differently depending on the purpose, so the present invention is not particularly limited thereto.

Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiments presented herein, and those skilled in the art who understand the spirit of the present invention can add components within the scope of the same spirit. , changes, deletions, additions, etc. may easily suggest other embodiments, but this will also fall within the scope of the present invention.

10: graphite 20: nanoparticles
30: catecholamine layer 40, 40': polymer layer
100: heat dissipation filler 101,101': graphite composite
200: polymer matrix 300, 301, 302, 303: metal support layer
311,312,313,314: protrusion 400: protective coating layer
1000,1001,1002,1003: graphite-polymer composite

Claims (16)

a polymer matrix formed of a thermoplastic polymer compound;
It is injection molded together with the thermoplastic polymer compound so that at least one surface perpendicular to the thickness direction forms an interface with the polymer matrix, and a part of the polymer matrix is disposed inside the hole in order to increase the bonding force with the polymer matrix at the interface in the thickness direction A metal support layer comprising a plurality of anchor holes having a diameter of 1 to 50 mm penetrating the upper and lower portions, and a protrusion formed to extend upwardly from at least a portion of an edge of a part or all of the anchor holes to function as an anchor in a polymer matrix; and
A graphite-polymer composite comprising a; a heat dissipation filler comprising graphite dispersed in the polymer matrix. delete The method of claim 1,
The protrusion is a graphite-polymer composite in which at least a portion of the metal support layer is cut. The method of claim 1,
The graphite is bonded to the graphite surface and is included in the form of a graphite composite further comprising nanoparticles that function as anchors at the interface formed with the metal support layer and a catecholamine layer covering the nanoparticles. Graphite-polymer composite material. Claims 1, 3 and 4 according to any one of the graphite-heat dissipation member comprising a polymer composite material. delete delete delete delete delete delete delete delete delete delete delete

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